the two recent deaths are likely to be from the stress of the move with the ich they already had. The other ones shouldnt be from iron in the water unless its in really high concentrations. If your worried though definetly use carbon, treat with salt and temp., and if that doesnt work use 1/2 dose of formalin. Fat clowns can handle full dose but sick fish that have been sick for a while might not like it much and increase the oxygen in your tank, it looks like the current in your tank is good but the surface isnt getting agitated that much.
good luck and keep us posted